Tool handle attaching and shockabsorbing means



Oct. 11, 1938. E, Ml HOLFELNE'R 2,133,095

' 'OLHANDLE ATTAGHING AND SHOCK ABSORBING MEANS Filed July 2, 1936 IN VEN TOR. Y 17%3 EdWafdM/f/fe/Zf Y /vua r M ATTORNEYSi Patented Oct. 11, 1938 UNITED STATES PATENT OFFICE TOOL HANDLE ATTACHING AND SHOCK- ABSORBING MEANS Application July 2, 1936, Serial No. 88,575

4 Claims. -(Cl. 145-108) My invention relates to tool handle attaching and shock-absorbing means. It has to do more particularly with means for securing a tool blade, such as a saw blade, in a handle and with means 5 for absorbing shocks which result from using the blade and to substantially preventl such shocks from reaching the handle. Although I shall describe my invention as particularly applicable to a saw, it is to be understood that it is not limlU ited thereto.

` In the ordinary handsaw, one end of the metal blade is inserted in a slot in a handle made of wood or the like and is secured in the handle by means of screws or rivets. 'I'he screws are initially tightened to such an extent that the blade will be tightly gripped in the handle. However,

when the wood of the handle contracts, due to changes in moisture conditions, the screws become loose and therefore the blade becomes loose in the handle. This looseness is made more pronounced because of the fact that the holes in the saw blade through which the screws pass must be made slightly larger than the diameter of the screws so as not to injure the threads on the screws. At a later period, the wood of the handle may again expand to such an extent that the handle will again be tight on the blade. In fact, it may expand to such an extent that the screws will be so tight that cracking of the handle will result. These screws are usually made in two pieces, and when the handle contracts so that they become loose there is danger that the head of the screw will fall off due to the fact that the vibration resulting from use of the tool will cause it to rotate.

Another disadvantage of saws and other similar tools made heretofore resides in the fact that there has been no means provided for absorbing the shock transmitted from the blade to the handle during use of the tool. These shocks transmitted to the handle cause fatigue and may even cause some injury to the hand of the workman using the tool.

One of the objects of my invention is to provide a tool of the type indicated embodying a blade and a handle member, the blade being secured to the handle member by means of screws, rivets, or similar securing means, means also being provided to compensate for expansion and contraction of said handle and to prevent the screws or similar means from becoming loose thereby causing the handle to be firmly secured to the blade at all times.

Another object of my invention is to provide a tool of the type indicated embodying a blade and a handle secured together in the manner indicated wherein means is provided for absorbing the shocks resulting when the blade is used and for substantially preventing them from reaching the handle.

In its preferred form my invention contemplates the provision of a tool embodying a blade having one end that ts in a recess formed in a handle member of wood or the like. The blade is secured in the recess in the handle member by means of screws which pass transversely through corresponding openings formed in the handle member and the end of the blade. Resilient material is preferably disposed between the blade and the wall of the recess formed in the handle in which it is inserted. This resilient material is adapted to compensate for expansion and contraction of the handle in order that the blade will always tightly t within the recess and is adapted to absorb shocks which are imparted to the blade.

The screws are surrounded with resilient material so that the metal blade will not contact with the metal screws but, on the other hand, there will be a resilient cushion between these members which will serve to absorb shocks imparted to the blade. However', the resilient material surrounding the screws serves also to compensate for expansion and contraction of the handle and to maintain the screws tight at all times.

The preferred embodiment of my invention is illustrated in the accompanying drawing wherein similar characters of reference designate corresponding parts and wherein:

Figure 1 is a perspective view partly broken away showing a portion of a handsaw blade with a handle applied thereto according to my invention.

Figure 2 is a section taken substantially along line 2-2 of Figure l.

Figure 3 is a plan view of a member adapted to be inserted in the blade-receiving recess formed in the handle.

Figure 4 is a perspective view of a member adapted to be inserted in a screw-receiving openmg.

With reference to the drawing, I have illustrated a handsaw embodying a blade l and a handle member 2 of usual construction. The blade l has its end inserted in a recess or openended slot 3 formed in the handle 2 in the usual manner. In order to secure the blade in the slot formed in the handle a plurality of transversely extending screws 4 are provided. These screws pass through corresponding openings 5 and 6 formed in the handle and the blade respectively.

It will be noted from the drawing that between the blade I and the walls of the slot 3 is disposed. a cushion of material `I. This material may be of any suitable flexible material, preferably resilient, for example, rubber. It will be noted that the material 'I 4extends over the side surfaces i compress the rubber cushion. Thus, if the hanf in the blade.

dle member 2 contracts or shrinks so that the slot 3 will become larger, the rubber cushion will ex pand to compensate for this contraction of the handle and will maintain a tightt between the blade and the handle. On the other hand, if the handle expands and thereby mak-es the slot 3 smaller, it will not be cracked or otherwise injured because the rubber cushion 'I will be compressed. Obviously, the rubber cushion will absorb Vthe shocks imparted to the blade I during the use of the saw, and will substantially prevent said shocks from reaching the handle 2.

Each of the screws 4 embodies a screw portion having a head 9 and a threaded end Il) and a nut portion II embodying a head I2 and a tubular portion I3 which is threaded onto the threaded end Il) ofthe screw portion 8. In order to provide means for substantially preventing the shocks imparted to the blade I from being transmitted to the screws 4 and thence to the handle and in ord-er to prevent the screws from coming loose at any time I provide a member I4 which surrounds each screw. This member I4 is preferably made of the same material as th-e cushion l. The resilient member I4 entirely surrounds the shank of the screw portion 8 of the screw. vThe outer surface of this member I4 (Figure 2) gradually tapers inwardly towards the inner end thereof so that the member is of substantially frusto-conical form. Ribs I6 are provided on the screw portion 8 to prevent rotation of the member i4 thereon, the ribs extending into the material of the member I4. The walls of the openings 5 in the handle 2 are tapered the same as the tapered outer surface of the member I4. It will be noted that the resilient member I4 extends a considerable distance inwardly past the point Il where the threads on the member 8 terminate. It will also be noted that the extreme inner end of the member I4 is bevelled as at I8, the bevel extending towards the center of the screw and outwardlyr towards the head 9.

The member Ill is preferably molded on the screw portion 8. The screw portion 8 carrying member I4 is inserted in the openingsv 5 of the handle and will extend through the opening 6 It will be noted that the member I4 will extend entirely through the blade. The member I4 is preferably of such thickness that it must be compressed when it is placed in the openings 5 and 6. The nut portion Il of the screw is then threaded on the threaded end IG of member 8. The member I4 is of such a length that before the screw is tight in the handle,rthe.

end of the tubular portion I3 of the nut thereof will contact with the bevelled end I3 of the member I4. This bevel i8 is Yin such a direction that upon tightening of the nut II on the screw portion 8, the material of the member I4 will be forced outwardly away from the center of the screw so that it will contact firmly with the wall of of the handle.

the opening 6 formed in the blade I and also with the walls lof openings 5. The member I4 will thus be compressed. Furthermore, the head 9 on screw portionV 8 will tend to force the member I4 inwardly when the screw is tightened. This will force the member I4 tightly in contact with the walls of the opening 5, du-e to the corresponding taper of the outer surface of member I4 and the walls of openings 5. Also, the head Q pressing inwardly on the outer end of member I4 will aid in forcing the member I4 tightly into contact with the wall of opening 6 in the blade.

It will be apparent that because the member I4 is compressed when the screw is initially tightened, if the handle 2 contracts or shrinks, there- 1 by causing openings 5 to become larger, the member I4 will expand to compensate for contraction Consequently, the screw will always be tight in the handle. On the other hand,

if the handle expands, thereby causing openings 5 tobecome smaller, the material of the member I4 will further compress and no injury to the handle will result. The inner end of the tubular portion I3 of the head of the screw will always bear against the end of member I4 firmly so that there will be no danger of accidental turning and loosening of the head portion of the screw. If

vthe handle expands to an unusual extent so that the heads 9 and I2 bear on the handle with unusual force, the resilient member 'I' will compress to such an extent as to prevent splitting of the. handle. The resilient tubular member I4 also serves as a cushion element to prevent shocks beingV transmitted from the blade I through the screw and thence to the'handle member.

In Figure 3, I illustrate a structure which will facilitate insertion of the rubber insert into slot 3. This structure comprises a resilient member 1a, which is the same as member 'I, but which is secured to a U-shaped member 'ib formed of resilient metal. The member la may be secured to member Ib in any suitable manner such as by vulcanizing. It will be apparent that because the resilient member Ia is secured to the metal member lb, which surrounds member la, it will facilitate insertion of member 'Ia in the slot 3.

In Figure 4, I show a modified resilient structure for surrounding each of the screws 4. This structure embodies a resilient member E40, which is the same as member Ill. However, this member 54a is substantially surrounded by a member Illb of substantially frusto-conical form which is made of resilient metal. A slot Ilic is formed in the member Ib. This composite structure will` surround each of the screws 4, in the same manpansion and contraction of member Elib at the time that the resilient contracts.

It will be apparent from the above that I have provided a tool embodying a blade which is inmember Ilia expands and serted in a recess in a handle portion and held therein by screws or similar securing means, `the tool being provided with means for veffectively preventing the handle member from becoming loose on the blade and for preventing loosening of the securing means. This means also functions to cushion the handle against shock imparted to the blade.

Although I have described this invention as being particularly applicable to ordinary handsaws it will be apparent that it is applicable to any of the Various types of saws which are provided with handles. Furthermore, it is not limited in its application to saws. It may be applied to any tool wherein a blade or similar member is held in a handle member by means of screws, rivets or similar securing means.

Many other advantages will be apparent from the preceding description, the drawing and the following claims.

Having thus described my invention, what I claim is:

1. In a tool of the type described, a blade member made of metal, a handle member, the blade having a portion tting into a recess formed in said handle member, an insert of resilient material between all of the surfaces of said recess and the adjacent surfaces of said blade, said insert of resilient material being of such thickness that it is compressed when the blade is positioned in suoli recess, a plurality of screws for securing the blade in said recess extending transversely through aligning openings formed in said blade and said handle member, each of said screws embodying a screw portion and a nut portion, said screw portion embodying a head and a shank which is threaded at its inner end, said nut portion embodying a head and an internally threaded tubular portion adapted to be screwed onto the threaded end of the screw portion, a member formed of resilient material disposed in surrounding relation to the screw portion, said member having a tapered outer surface which cooperates with a correspondingly tapered surface on the wall of the opening in the handle member in which it is disposed, said resilient member extending inwardly past the point on the screw portion where the threads terminate, the extreme inner end of said resilient member having a conical depression therein forming a beveled edge, said resilient member being of such length that the inner end of the nut portion will contact with the bevelled end thereof before the screw is completely tightened.

2. In a tool of the type described, a blade member, a handle member, means for securing the blade member to the handle member, said means comprising screws which extend through aligning openings in said handle member and blade member, each of said screws embodying a screw portion and a nut portion, said screw portion embodying a head and a shank which is threaded at its inner end, said nut portion embodying a head and an internally threaded tubular portion adapted to be screwed onto the threaded. end of the screw portion, a member formed of resilient material disposed in surrounding relation to the screw portion, said member having a tapered outer surface which cooperates with a correspondingly tapered surface on the Wall of the opening in 'the handle member in which it is disposed, said resilient member extending inwardly past the point on the screw portion where the threads terminate, the extreme inner end of said resilient member having a conical depression .therein forming a bevelled edge, said resilient member being of such length that the inner end of the nut portion of the screw will contact with `the bevelled end thereof before the screw is completely tightened.

3. In a tool of the type described, a blade member, a handle member, means for securing the blade member to the handle member, said means comprising screws which extend through aligning openings in said handle member and blade member, each of said screws embodying a screw portion and a nut portion, said screw portion embodying a head and a shank which is threaded adjacent its inner end, said nut portion comprising a head and a tubular extension which is internally threaded and is adapted to be screwed onto the threaded shank or the screw portion, a member formed of non-metallic inherently resilient material disposed in surrounding relation to the main portion of the screw and adapted to extend through the opening in the blade, said resilient member extending inwardly past the point on the screw portion where the threads terminate, said resilient member being of such length that the inner end of the nut portion of the screw will contact with the inner end thereof before the screw is completely tightened.

4. In a tool of the type described, a tool member, a handle member, means for securing the tool member and the handle member together, said means comprising securing members which extend through aligning openings in said handle member and tool member, and a member formed of non-metallic inherently resilient material disposed in surrounding relation to each of said securing means, said member being substantially surrounded by a resilient member formed of metal, said metal member being adapted to contact with the edge of the cooperating opening in the tool member and being adapted to protect said non-metallic material.

EDWARD M. HOLFELNER 

